Browsing by Author "Kahimba, F. C."

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Accuracy of Giovanni and Marksim software packages for generating daily rainfall data in selected bimodal climatic areas in Tanzania
(Tanzania Journal of Agricultural Sciences, 2014) Kahimba, F. C.; Tumbo, S. D.; Mpeta, E.; Yonah, I. B.; Timiza, W.; Mbungu, W.
Agricultural adaptation to climate change requires accurate, unbiased, and reliable climate data. Availability of observed climatic data is limited because of inadequate weather stations. Rainfall simulation models are important tools for generating rainfall data in areas with limited or no observed data. Various weather generators have been developed that can produce time series of climate data. Verification of the applicability of the generated data is essential in order to determine their accuracy and reliability for use in areas different from those that were used during models development. Marksim and Giovanni weather generators were compared against 10 years of observed data (1998-2007) for their performance in simulating rainfall in four stations within the northern bimodal areas of Tanzania. The observed and generated data were analyzed using climatic dialog of the INSTAT program. Results indicated that during the long rain season (masika) Giovanni predicted well the rainfall amounts, rainy days, and maximum dry spells compared to Marksim model. The Marksim model estimated seasonal lengths much better than the Giovanni model during masika. During short rain season (vuli), Giovanni was much better than Marksim. All the two software packages had better predictions during masika compared to vuli. The Giovanni model estimated probabilities of occurrence of rainfall much better (RMSE = 0.23, MAE = 0.18, and d =0.75) than Marksim (RMSE = 0.28, MAE = 0.23, and d = 0.63). The Marksim model over-predicted the probabilities of occurrence of dry spells greater than seven days (MBE = 0.17) compared to the Giovanni model (MBE = 0.01). In general the Giovanni model was more accurate than the Marksim model in most of the observed weather variables. The web based Giovanni model is better suited to the northern bimodal areas of Tanzania. The Marksim model produced more accurate climatic data when the long-term average climate data are used as input variables. This study recommends the use of rainfall data generated using Giovanni software over Marksim, for areas receiving bimodal rainfall regimes similar to the northern bimodal areas of Tanzania.
Adoption and scaling-up of conservation agriculture in Tanzania: Case of Arusha and Dodoma regions
(Scientific Research, 2014-02-21) Kahimba, F. C.; Mutabazi, K. D.; Tumbo, S. D.; Masuki, K. F.; Mbungu, W. B.
A study was conducted to assess the adoption and scaling-up of Conservation Agriculture in Arumeru district, Arusha region, northern Tanzania and Chamwino and Dodoma Urban districts in Dodoma region, Central Tanzania. The study employed structured questionnaire survey and key informant interviews as the main data collection methods. Data analysis was done descriptively to determine factors that influence the adoption. Results showed that farmers in Arusha have highly adopted terraces, minimum tillage and cover cropping whereas their counterparts in Dodoma have highly adopted large planting pits, minimum tillage, and rippers. The intensity of adoption in Arusha is higher for the wealthy compared to the poor while in Dodoma the wealth status was not a factor that influenced adoption of the Conservation Agriculture (CA) technologies. The process of technology adoption should include the use of various participatory methods including farmer field schools, experimental plots, farmer exchange visits, and training of trainers among others. Use of farmer groups, incentives, and support instruments such as Savings and Credit Co-operative Society (SACCOS) or warehouse receipts systems are also important to ensure that farmers realize some acceptable profits from their efforts. Involvement of various stakeholders is also very important including local governments and agricultural change agents at national, regional, district, ward and village levels. Hence, the intention to promote CA technologies should not only look at the economic importance, but also its socio-economic importance to the local people in the area. Their desire to adopt and out-scale a technology should be among the most important investment factors that the government and development partners should consider.
Application of self-organizing-maps technique in downscaling GCMs climate change projections for Same, Tanzania
(2010) Tumbo, S. D.; Mpeta, E.; Mbillinyi, B. P.; Kahimba, F. C.; Mahoo, H. F.; Tadross, M.
High resolution surface climate variables are required for end-users in climate change impact studies; however, information provided by Global Climate Models (GCMs) has a coarser resolution. Downscaling techniques such as that developed at the University of Cape Town, which is based on Self-Organizing Maps (SOMs) technique, can be used to downscale the coarse-scale GCM climate change projections into finer spatial resolutions; but that must be combined with verification. The SOM downscaling technique was employed to project rainfall and temperature changes for 2046-2065 and 2080-2100 periods for Same, Tanzania. This model was initially verified using downscaled NCEP reanalysis and observed climate data set between 1979 and 2004, and between NCEP reanalysis and GCM controls (1979 - 2000). After verification, the model was then used to downscale climate change projections of four GCMs for 2046-2065 (future-A) and 2080-2100 (future-B) periods. These projections were then used to compute changes in the climate variables by comparing future-A and B to the control period (1961-2000). Verification results indicated that the NCEP downscaled climate data compared well with the observed data. Also, comparison between NCEP downscaled and GCM downscaled showed that all the four GCM models (CGCM, CNRM, IPSL, and ECHAM) compared well with the NCEP downscaled temperature and rainfall data. Future projections (2046-2065) indicated 56 mm and 42 mm increase in seasonal total rainfall amounts for March-April-May (MAM) and October-November-December (OND) (23% and 26% increase), respectively; and a temperature increase of about 2°C for both seasons. Furthermore, it was found that during MAM there will be a decrease in dry spells by 2 days, and an increase in seasonal length by 8 days, while for OND, there will be also 2 days decrease in dry spells, and 40 days increase in the seasonal length. The results for future-B shows a 4°C rise in temperature, and 46.5% and 35.8% increase in rainfall for MAM and OND, respectively. The results imply a better climatic future for the area because of the increase in the amount of rainfall and decrease in dry spells. However, it is suggested that further investigations are required to see if the projected changes will have real positive effects in agricultural production and also identify better agronomic practices that will take advantage of the opportunities.
Effects of fertilizer micro-dose and in situ rain water harvesting technologies on growth and yield of pearl millet in a semi-arid environment
(Springer, 2020-03) Chilagane, E. A.; Saidia, P. S.; Kahimba, F. C.; Asch, F.; Germer, J.; Graef, F.; Swai, E.; Rweyemamu, C. L.
Declining soil fertility and low rainfall are key constraints to crop production and are threatening food security in semi-arid areas. Applying inorganic fertilizer at reduced amount (micro-dose) and in situ rainwater harvesting using infiltration pits (IP) or tied ridges (TR) are low-input strategies to cope with these constraints. This work investigates the effect of integrating fertilizer with in situ rainwater harvesting technologies on pearl millet growth, yield and household profitability among Tanzanian smallholder farming communities. Split plot field experiments were conducted from 2015 to 2017 cropping seasons. Flat cultivation (FC) with zero fertilizer application resulted in lowest grain yield ranging from 297 to 453 kg/ha and in a negative net profit (NP). The highest yield of 2202 kg/ha was obtained upon the use of recommended rate under IP, but it resulted in negative NP. Infiltration pits under 25% micro-dose resulted in relative higher grain yield (778–2202 kg/ha) compared to TR (887–1915 kg/ha) and FC (592–1144 kg/ha); despite higher yield, it resulted in negative NP. Tied ridges and FC with micro-dose at 25% of recommended rate had a yield advantage ranging from 537 to 959 kg/ha and 295 to 455 kg/ha, respectively, compared to farmer practices, and both resulted in positive NP. The use of micro-dose at 25% of recommended rate along with TR or FC which gave higher grain yield and NP compared to farmers practice is recommended to resource-poor farmers for improved pearl millet productivity.
Expert-based ex-ante assessments of potential social, ecological, and economic impacts of upgrading strategies for improving food security in rural Tanzania using the ScalA-FS approach
(Springer Science, 2017) Graef, F.; Uckert, G.; Schindler, J.; König, H. J.; Mbwana, H. A.; Fasse, A.; Mwinuka, L.; Mahoo, H.; Kaburire, L.; Saidia, P.; Yustas, Y. M.; Silayo, V.; Makoko, B.; Kissoly, L.; Lambert, C.; Kimaro, A.; Sieber, S.; Hoffmann, H.; Kahimba, F. C.; Mutabazi, K. D.
Subsistence farmers in sub-Saharan Africa are highly vulnerable to food insecurity given their low adaptive capacity against ecological and socio-economic shocks. Therefore, food security is one of their main challenges. Participatory action research across food value chains (FVCs) can help stabilize and enhance food security by developing upgrading strategies (UPS) that enhance specific aspects of crop production, post-harvest processing, marketing, income generation, and consumption. However, prior to their widespread adoption or upscaling, UPS need holistic understandings of their potential social, ecological, economic, and institutional challenges and opportunities in target areas. This article reports the application of the BScalA-FS^ tool, which assessed the potential success of selected UPS using assessment criteria developed by agricultural scientists and local farmers in a participatory process in Tanzania. This work is embedded in a larger participatory research project conducted in semi-arid and sub-humid ecological settings of the Dodoma and Morogoro regions of Tanzania. Results from the assessment of the potential impact of the UPS differed strongly between the UPS and the social, economic and environmental assessment criteria, but only slightly between semi-arid and sub-humid regions. The positive impacts of food-securing UPS centre on productivity and income generation. Rain water harvesting, fertilizer micro-dosing, optimized weeding, and promotion of kitchen gardens were expected to have the highest impacts after implementation. The ScalA-FS ex-ante assessments provide a knowledge base about potential impacts, as well as the potential bottlenecks to address during the implementation of UPS.
A gendered analysis of perception and vulnerability to climate change among smallholder farmers: the case of Same district, Tanzania
(2015-02-16) Mnimbo, T. S.; Mbwambo, J.; Kahimba, F. C.; Tumbo, S. D.
Climate change affects women and men differently. However, there are few location-specific studies that can support interventions or policy development that can tackle this issue. To help build that body of knowledge, this article looks at gender-differentiated vulnerability among smallholder farmers in one sub-Saharan African country: Tanzania. Data were collected through household questionnaires, key informant interviews, and focus group discussions in Same District, northern Tanzania. Results revealed notable inequalities distributed across genders. Women bear the biggest burden from climate change impacts. For example, women shoulder 63% of productive tasks, such as ploughing and crop sowing, compared to 28% by men. On the other hand, resource ownership and expenditure are male dominated. The results highlight the need for governments and NGOs to address gender disparities in policies designed to strengthen the capacity of households to cope with vulnerability to climate change impacts.
Impact of projected climate change on agricultural production in semi-arid areas of Tanzania: A case of Same district
(2012) Tumbo, S. D.; Kahimba, F. C.; Mbilinyi, B. P.; Rwehumbiza, F. B.; Mahoo, H. F.; Mbungu, W. B.; Enfors, E.
Sub-Saharan Africa is one of the most vulnerable regions in the World to climate change because of widespread poverty and limited adaptive capacity. The future climate change is likely to present an additional challenge to the agricultural sector. Therefore, the effects of climate change on the current agronomic management practices were investigated using Same District, Tanzania as a case study area. APSIM software was used to investigate the response of maize (Zea mays L.) yield to different agronomic management practices using current and future (2046 - 2065) climate data. The climate change projections data from global climate models were downscaled using self-organising maps technique. Under the conventional practices, results show that during long rainy season (from March to May) there is yield decline of 13% for cultivar Situka, no change for cultivar Kito and increase of 10% and 15% for cultivars Sc401 and TMV1, respectively. Under the recommended practices, cultivars TMV1 and Sc401 are projected to register a 10% yield increase whereas cultivars Situka and Kito are projected to register a decrease of 10% and 45%, respectively. Also, under both conventional and recommended management practices, results showed that during short rainy season (from October to December/January) all cultivars are projected to register between 75% and 146% increase in maize yields. This implies that future climate change is going to have positive effects on current management practices during short rainy seasons and it will have negligible impact during long rainy seasons.
Integrated assessment of climate change impacts and adaptation in agriculture: the case study of the Wami River Sub-basin, Tanzania
(Springer Nature Switzerland AG, 2020) Tumbo, S. D.; Mutabazi, K. D.; Mourice, S. K.; Msongaleli, B. M.; Wambura, F. J.; Mzirai, O. B.; Kadigi, I. L.; Kahimba, F. C.; Mlonganile, P.; Ngongolo, H. K.; Sangalugembe, C.; Rao, K. P. C.; Valdivia, R. O.
This study evaluates the impacts of climate change and an adaptation strategy on agricul- ture in the Wami River sub-basin in Tanzania. This study uses the Agricultural Model Improvement and Inter-comparison Project (AgMIP) framework that integrates climate, crops and economic models and data using a novel multi-model approach for impact assess- ment of agricultural systems under current and future conditions. This study uses five Global Circulation Models (GCMs) from the fifth phase of the Coupled Model Inter-comparison Project (CMIP5), two crop simulation models, and one economic impact assessment model. In this study, a representative agricultural path- ways (RAP) that characterises future condi- tions following ‘business-as-usual’ trends was developed and used to model future agricul- tural systems in the Wami River sub-basin. Results show that by mid-century, the maxi- mum and minimum temperatures will increase by 1.8–4.1 °C and 1.4–4.6 °C, respectively. Rainfall is predicted to be variable with some places projected to increase by 12%, while in other areas it is projected to decrease by 14– 28%. Maize yields under these conditions are projected to decrease by 5.3–40.7%. Results show that under current conditions, 50–60% of farm households are vulnerable to losses due to climate change. The impacts of climate change on poverty and per capita income are also projected to be negative. Under the current production system, poverty rates were pro- jected to increase by 0.8–15.3% and per-capita income to drop by 1.3–7.5%. Future socio-economic conditions and prices offset the negative impacts of climate change. Under future conditions, the proportion of households vulnerable to loss is estimated to range from 25 to 50%. Per-capita income and poverty rates are expected to improve under the future climate change conditions. Poverty rates would decrease between 1.9 and 11.2% and income per-capita would increase between 2.6 and 18.5%. The proposed future adaptation pack- age will further improve household liveli- hoods. This integrated assessment of climate change projections using the improved meth- ods and tools developed by AgMIP has con- tributed to a better understanding of climate change and adaptation impacts in a holistic manner.
Participatory land-use planning: integrating expert-oriented and community-based tools for sustainable land management in Kilimanjaro Region
(Department of Soil Science Sokoine, University of Agriculture, Tanzania., 2015) Mahonge, C.P.1; Kashaga, R.A.L.; Kahimba, F. C.; Semu, Ernest; Mkanda, F.X.; Sangeda, A.Z
Tanzania like other countries globally has witnessed a paradigm shift in natural resource planning and management from state-centric to community based approach. The shift was inevitable following the experienced inadequacies of the state capacity in-terms of human and financial resources to manage natural resources in a sustainable way, which in turn exacerbate natural resource degradation. It was consequently envisaged that giving people stake in the planning and management endeavors would help fill the gap. While the manifestation of this shift in the country started since the mid-1990s, little empirical evidence exists on the value of participatory land use planning in ensuring sustainable management of natural resources. This study provides an account on the way participatory land use planning through Sustainable Land Management (SLM) project in Kilimanjaro region has integrated expert-oriented (GIS) and community-based (PRA) tools as a move towards sustainable land management in the region.
Testing of decision making tools for village land use planning and natural resources management in Kilimanjaro region
(Scientific Research, 2014) Sangeda, A. Z.; Kahimba, F. C.; Kashaga, R. A.; Semu, E.; Mahonge, C. P.; Mkanda, F. X.
This paper focuses on participatory testing of decision making tools (DMTs) at village level to assist in development of land use plans (LUPs) for sustainable land management (SLM) in Kilimanjaro Region, Tanzania. Data were collected using conditional surveys through key informant interviews with the project’s district stakeholders in each district, focused group discussions with selected villagers and participatory mapping of natural resources. Soil health, land degradation, carbon stock, and hydrological conditions were assessed in the seven pilot villages in all seven districts using DMTs as part of testing and validation. Results indicated soils of poor to medium health, and land degradation as portrayed by gullies and wind erosion in lowlands and better in uplands. Carbon and forest disturbance status could not be assessed using one-year data but hydrological analysis revealed that water resources were relatively good in uplands and poor in the lowlands. Challenges with regard to land use include increased gully erosion, decreased stream flow, reduced vegetation cover due to shifting from coffee with tree sheds to annual crops farming, cultivation near water sources, and overgrazing. Empowering the community with decision making tools at village level is essential to ensure that village land uses are planned in a participatory manner for sustainable land and natural resources management in Kilimanjaro and other regions in Tanzania.